# custom queue byte calculations

hi all

i am doing custom quequing byte count calculations , the value i got is 2.015 .... i have rounded it to 3 ..but is seems the answer key has rounded it to 2 .

As per cisco doc

Step 3 A fraction in any of the ratio values means that an additional packet will be sent. Round up the numbers to the next whole number to obtain the actual packet count.

what you think ... do we only to consider only one digit afer decimal point ?

• what are your other ratios value for calculating byte count ?

• Allocate the bandwidth with custom queue

Allocate 20% of bandwidth to  FTP with a packet size of 1500 bytes

Allocate 30% of bandwidth to  HTTP traffic with a packet size of 600 bytes

Allocate 40% of bandwidth to UDP port 5001 with a packet size of 300 bytes

Allocate 10% of bandwidth to other types of traffic with a packet size of 1500 bytes

The traffic listed above is transmitted out of s0/0 interface

Step 1

Percentage / byte

20/1500 = 0.0133

30/600 = 0.0.5

40/300= 0.133

10/1500= 0.0066

Step2

2.015, 7.57, 20.151, 1

Step 3

3 , 8 ,21 , 1

Byte count = 3000, 4800, 6300, 1500

ref http://www.cisco.com/en/US/docs/ios/qos/configuration/guide/congstion_mgmt_oview_ps6350_TSD_Products_Configuration_Guide_Chapter.html#wp1001355

• In your step 3, if you take these values are 3,8,21,1 your byte count will be 4500,4800,6300,1500 and BW allocation will be 26.3,28,36.8,8.7. Clearly this is not desirable as per requirement. Because here 2.015 is round up to 3 which is too far from 2.

Your ultimate goal for this task is to get the desirable BW allocation which is 20,30,40 and 10 percent try to make the numbers in step 3 such that they will make this percent.

Sometime we have to use reverse logic to do this.

We have the following options in step 2.

1. 3,8,21,1  ---->BW % is--->26.3, 28, 36.8,  8.7

2. 2,8,21,1  ---->BW % is--->19.2, 30.7, 40.38, 9.6

3. 2,8,20,1  ---->BW % is--->19.6, 31.3, 39.2, 9.8

etc.

Take the best option which makes up the requirement of BW allocation.

In the above list it seems that both 2 and 3 are very close to the requirement.

Thanks